Mooring Safety-A handy Summary of MGN 592

A quick detour in this blog , a detour away from Maritime Security to look at Mooring safety, a detour instigated by the issue by the UK MCA of a new M Notice. 

Mooring, towing or hauling equipment on all vessels

The UK Maritime and Coastguard Agency have recently re-issued their guidance on mooring operations in the form of a new M Notice-  MGN 592, which replaces MGN 308.

Click here for MGN 592>

The notice contains some really useful information on mooring equipment and its use, information that is useful to all those involved in vessel’s mooring operations even those sailing under non UK flags.

“Greater emphasis should be given to considering the safety aspects of mooring and towing systems as a whole rather than the individual safety aspects of component parts.” MGN 592


Design and Installation of Mooring Equipment

How should winches of windlasses be designed?

Load-They should be constructed to give warning of undue strains by stalling at well below the designed maximum safe working load of the weakest element in the system and to afford further protection by walking back at about the design load- that is the  breaking strength of the mooring rope, tow line, or hawser whichever is applicable,

Layout-The layout should be such as to avoid the need for anyone to be stationed or work in the bight or warp of rope formed by the lead from the winch or windlass round and through the fairleads and over-side.

Failure-The consequences of failure in any part of the system should be carefully considered and effective precautions taken.


How should pedestal roller fairleads, lead bollards, and mooring bitts be designed?

  • Be properly designed to meet all foreseeable operational loads and conditions;
  • Be Correctly sited to minimise the need for complex mooring line configurations;
  • As far as reasonably practicable, a dedicated fairlead should be provided for each mooring line;
  • Be effectively secured to a part of the ship’s structure which is suitably strengthened.

Repair and maintenance

What must owners, operators, masters and skippers should ensure?

  • That all mooring, towing and hauling equipment are covered by a regular maintenance programme.
  • That equipment should be regularly inspected for wear, damage, deflection and corrosion.


What are the maintenance requirements for ropes?

  • All ropes, wires, and stoppers that are used for hauling, towing or mooring operations should be in good condition;
  • Ropes should be frequently inspected for both external wear and tear between strands;
  • Wires should be regularly treated with suitable lubricants and inspected
    for deterioration internally and broken strands externally;
  • Splices in both ropes and wires should be inspected regularly to check they are intact.

What should be considered when deck repairs are undertaken?

  • Particular care should be taken when repairing deck areas, especially those fitted with bollards or equipment requiring a strong substantial base;
  • Classed ships must carry out such repairs with the knowledge of, and under the supervision of Class;
  • Ships under certification by a Certifying Authority Should undertake such repairs in a similar way.

Safe Use of Equipment:


What Precautions to be taken before and during mooring, towing and hauling operations?

  • All operations should be pre-planned, and a risk assessment of the operation should be completed, especially  where unusual or non-standard mooring arrangements are to be used;
  • Careful thought should be given to mooring, towing and hauling arrangements, so that the leads used are those most suited and will not create sharp angles;
  • Ropes and wires should not be fed through the same leads or bollards.
  • Fairleads which have previously been used for wires should be checked to ensure that they have no sharp metallic areas on tension surfaces prior to being used for ropes.

What safety precautions should be taken  when mooring equipment is under load?

  • Personnel essential to the operation should as far as reasonably practicable be able to stand in a protected position;
  • Other persons who have no involvement with mooring, towing or hauling operations, should  be kept well clear of the area;
  • Immediate action should be taken to reduce the load if signs of excessive strain appear in any part of the system.

What should be considered by the person in charge of mooring operations?

  • Wherever practical the person in charge should avoid getting involved with the physical operations, so that they can retain an effective oversight;
  • Good communication must be maintained between all members of the mooring team.

Note- Operation of winches should be undertaken by competent personnel to ensure that excessive loads do not arise on mooring, towing and hauling lines.

How should wire and fibre ropes be joined?

A thimble or other device should be inserted in the eye of the fibre rope. Both wire and fibre rope should have the same direction of lay.


How should ropes and wires be used if stowed on reels?

  • Ropes and wires that are stowed on reels should not be used directly from stowage unless a split drum arrangement is available;
  • They should be run off and flaked out on deck in a clear and safe manner, ensuring sufficient slack to cover all contingencies;
  • if there is doubt of the amount required, then the complete reel should be run off.

What general principles are to be borne in mind when planning a mooring arrangement?

  • Breast-lines provide the bulk of athwartships restraint;
  • Back-springs provide the largest proportion of the longitudinal restraint;
  • Very short lengths of line should be avoided where possible, as such lines will take a greater proportion of the total load, when movement of the ship occurs;
  • Very short lengths may be compensated for by running the line on the bight.

What principles should be followed when heaving on a rope on a drum end?

  • One person should be stationed at the drum end;
  • For heaving moorings and large vessel operations, they should be backed up by a second person backing and coiling down the slack;
  • The line must be tended at all times.
  • In most circumstances up to three turns on the drum end are sufficient and an excessive number of turns should be avoided;
  • A wire on a drum end should never be used as a check wire.

What precautions should be taken when both wires and fibre ropes are used?

  • A wire should never be led across a fibre rope on a bollard;
  • Wires and ropes should be kept in separate fairleads or bollards.

How should stoppers be applied?

  • Natural fibre rope should be stoppered with a natural fibre stopper;
  • Man-made fibre rope should be stoppered with a man-made fibre stopper, but not polyamide;
  • The “West Country” method (double and reverse stoppering) is preferable for fibre ropes;
  • Wire moorings should be stoppered with chain, using two half hitches in the form of a cow hitch, suitably spaced with the tail backed up against the lay of wire, to ensure that the chain neither jams no opens the lay of the wire.

How should weighted heaving lines be used safely?

  • To prevent personal injury to those receiving heaving lines, the “monkey’s fist” at the weighted end should be made with rope only and must not contain added weighting material.
  • Under no circumstances is a heaving line to be weighted by items such as shackles,
    bolts, or  nuts.
  • Safe alternatives include a small high-visibility soft pouch, filled with fast-draining pea shingle or similar, with a weight of not more than 0.5kg.
  • Prior to the operation, the person in charge at the mooring stations should check that lines are not dangerously weighted. If any dangerously weighted lines are found, these should be removed and replaced with appropriate heaving lines.
  • Tug

What precautions should be taken when working with tugs?

  • It is important that those involved consider the safety of persons on both vessels.
  • All equipment used in towing operations, including messengers, should be regularly inspected and replaced if necessary;
  • Good communication between the tug and vessel  are important to ensure that the status of tow lines is understood by both vessels at all times to avoid unexpected loads being applied;
  • Ensure the bitts upon which the towing eye is to be placed are clear of ropes or wires;Note: Similar considerations need to be applied when working with any mooring operation where equipment out of direct control of the vessel is used.

Specific Risks

What are the precautions to be taken with regard  bights of rope and snap-back zones?

  • Personnel should not in any circumstances stand in a bight of rope or wire.
    When mooring, towing and hauling lines are under strain all personnel in the vicinity should remain in positions of safety, avoiding potential ‘snap-back’ zones.
  • All seafarers should be reminded that the whole of the mooring deck may be considered a danger zone and understandable and visible signage should remind all crew working on a mooring deck of this.
  • Viewing the mooring deck arrangement from a high point is recommended, so that
    potential snap-back zones can be identified.
  • Immediate action should be taken to reduce the load should any part of the system appear to be under excessive strain. Care is needed so that ropes or wires will not jam when they come under strain, so that if necessary they can quickly be slackened off.
  • Where a mooring line is led around a pedestal roller fairlead, the ‘snap back’ zone will change and increase in area. Where possible, lines should not be led round pedestals except during the operation of mooring the vessel, thereafter lines should be made up on bitts, clear of pedestals if at all possible.

Further Guidance

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